John Philip Holland (February 29, 1840 - August 12, 1914) was the engineer who developed the first true submarine accepted by the U.S. Navy

He was born in Liscanor, County Clare, Ireland and his brother Michael was active in the Fenian Brotherhood and introduced the inventor to the revolutionary group. Holland and the Fenians conceived a plan to develop a small submarine that could be sealifted on a large merchant ship to an area near an unsuspecting British warship. The submarine would then be released from the bottom of the merchant vessel and attack the warship.

Holland came to the United States in 1873. In 1875 his first submarine designs were submitted for consideration by the U.S. Navy, but turned down as unworkable. The Fenians, however, continued to fund Holland's research and development expenses at a level that allowed him to resign from his teaching post. In 1881 Fenian Ram was launched, but soon after, Holland and the Fenians parted angrily.

Holland continued to improve his designs and worked on several experimental boats prior to his successful efforts with the privately built Holland launched in 1898. This was the first submarine having power to run submerged for any considerable distance. She was purchased by the Navy after rigorous tests, and six more of her type were ordered.

After spending 57 of his 74 years working with submersibles, John Philip Holland died in Newark, New Jersey.